Lock



Feb. 9, 1937. E. N. JACOB] 2,070,2 76

LOCK

muuummuumuuuumu Edward AZ Jam] Patented Feb. 9, 1937 UNETED STTES PATENT OFFICE LOCK Application August 9,

2 Claims.

This invention relates to improvements in cylinder locks and has as an object to provide a novel manner of protecting the look against destruction by drilling.

Another object of this invention is to provide means for protecting a cylinder look against destruction by drilling which is entirely concealed from View.

With the above and other objects in view which will appear as the description proceeds, this invention resides in the novel construction, cornination and arrangement of parts substantially as hereinafter described and more particularly defined by the appended Claims, it being understood that such changes in the precise embodiment of the herein disclosed invention may be made as come within the Scope of the claims.

The accompanying drawing illustrates one complete example of the physical embodiment of the invention constructed according to the best mode so far devised for the practical application of the principles thereof, and in which:

Figure 1 is a View partly in side elevation and partly in longitudinal section through a cylinder look equipped with this invention; and

Figure 2 is a cross sectional View through Figure 1 on the plane of the line 2-2.

Referring now more particularly to the accompanying drawing, the numeral 5 designates a mounting member or casing of a conventional look cylinder which may be mounted in an outer shell or housing 6 and which is bored as at 'l to receive a cylinder 8. The cylinder 8 has a plurality of key operable tumblers 9 yieldingly 35 projectible from the periphery of the cylinder into longitudinal tumbler grooves 9' formed in the cylinder in communication With its bore, the tumblers being retractible out of the grooves to free the cylinder for rotation upon insertion of a proper key (not shown).

The cylinder also has the usual enlarged head til at its front end, the back portion H of which is disposed in a counterbore l2 in the casing 5. This counterbore |2 mounts a ring 13 of hardened metal capable of resisting drilling. The thickness of the ring IS which is stepped as shown to receive the back portion ll of the cylinder head is sufficient to extend from the circumference of the cylinder to a point closely adjacent the outer periphery of the casing or at least beyond the bottoms of the tumbler grooves. The hardened metal ring l3 thus protects the extended end portions of the tumblers 9 against being drilled out.

Particular attention is directed to the stepped 1935, Serial No. 35,489

Cross sectional shape of the ring. By virtue of this construction, only a narrow edge of the ring faces the front of the lock; I-lence, if an attempt is made to drill through the ring, the narrow edge presenting insufficient surface to permit a drill to get started woulddefiect the drill point and cause it to slip Off of the ring and thus further guard against destruction of the look by drilling.

To further protect the lock against destruction by drilling, the cylinder 8 has an armor plate t l mounted in the front end of the tumbler re- Ceiving Chamber l5. This plate extends entirely across the diameter of the cylinder with its ends fiush with the outer cylindrical surface thereof 15 so as not to interfere with rotation of the cylinder When the tumblers are properly retracted. The width of the armor plate M is substantially equal to that of the tumblers 9 and to permit passage'of the key, one side edge of its central portion is cut out as at lB.

Inasmuch as the ends of the armor plate le are flush with the outer cylindrical surface of the cylinder, it spans diametrically the distance between opposite portions of the hardened metal 25 ring [3 and in fact, Contacts the same to cooperate therewith in preventing the drilling of any portion of the tumblers.

From Figure' 2 it will be observed that only small areas of the cylinder at opposite sides of the tumblers are Vulnerable and these portions are so disposed with respect to the tumblers that drilling the same will not destroy the lock. A novei coaction thus exists between the hardened metal ring |3 and the armor plate M to afford complete protection for the tumblers of the look.

What I claim as my invention is:

1. In a lock, a bored casing having a tumbler receiving groove communicating with its bore, a look cylinder in the bore, the cylinder having an enlarged head on its front end, tumblers mounted transversely in the cylinder with their ends' projectible into the groove, and means to protect the tumblers against destruction by drilling from the front of the lock comprising a hardened metal ring inserted in the front of the casing to close the front end of the groove, said ring having an external diameter less than that of the cylinder head so as to be concealed thereby and having an internal diameter equal to that of the bore to form substantially a continuation of the bore, and a hardened metal plate completely embedded in the cylinder and extending diametrically through the cylinder directly ahead of the tumblers with its ends flush with the cylindrical surface of the cylinder and engaging the rear portion of the inner Wall of the hardened metal ring.

2. In a lock, a bored casing having a longitudinal tumbler receiving groove, a look cylinder in the bore, tumblers in the cylinder projectible into the groove, and a hardened metal ring mounted in the front end of the casing, said ring having a narrow cross section at its front end EDWARD N. J ACOBI. 

